/* $Id: bs3-cmn-RegCtxConvertToRingX.c $ */ /** @file * BS3Kit - Bs3RegCtxConvertToRingX */ /* * Copyright (C) 2007-2023 Oracle and/or its affiliates. * * This file is part of VirtualBox base platform packages, as * available from https://www.virtualbox.org. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation, in version 3 of the * License. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * * The contents of this file may alternatively be used under the terms * of the Common Development and Distribution License Version 1.0 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included * in the VirtualBox distribution, in which case the provisions of the * CDDL are applicable instead of those of the GPL. * * You may elect to license modified versions of this file under the * terms and conditions of either the GPL or the CDDL or both. * * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 */ /********************************************************************************************************************************* * Header Files * *********************************************************************************************************************************/ #include "bs3kit-template-header.h" /** * Transforms a real mode segment into a protected mode selector. * * @returns Protected mode selector. * @param uSeg The real mode segment. * @param bRing The target ring. */ static uint16_t bs3RegCtxConvertRealSegToRingX(uint16_t uSeg, uint8_t bRing) { uint16_t uSel; if ( uSeg == 0 || uSeg == BS3_SEL_R0_SS16) uSel = BS3_SEL_R0_SS16 + ((uint16_t)bRing << BS3_SEL_RING_SHIFT); else if ( uSeg == (BS3_ADDR_BS3TEXT16 >> 4) || uSeg == BS3_SEL_R0_CS16) uSel = BS3_SEL_R0_CS16 + ((uint16_t)bRing << BS3_SEL_RING_SHIFT); else if ( uSeg == (BS3_ADDR_BS3DATA16 >> 4) || uSeg == BS3_SEL_R0_DS16) uSel = BS3_SEL_R0_DS16 + ((uint16_t)bRing << BS3_SEL_RING_SHIFT); else if (uSeg == (BS3_ADDR_BS3SYSTEM16 >> 4)) uSel = BS3_SEL_SYSTEM16; else if (!(uSeg & 0xfff)) uSel = (uSeg >> (12 - X86_SEL_SHIFT)) + BS3_SEL_TILED; else if (uSeg == BS3_SEL_R0_DS16) uSel = (uSeg >> (12 - X86_SEL_SHIFT)) + BS3_SEL_TILED; else { Bs3Printf("uSeg=%#x\n", uSeg); BS3_ASSERT(0); return 0; } uSel |= bRing; return uSel; } /** * Transforms a protected mode selector to a different ring. * * @returns Adjusted protected mode selector. * @param uSel The current selector value. * @param bRing The target ring. * @param iReg Register index. */ static uint16_t bs3RegCtxConvertProtSelToRingX(uint16_t uSel, uint8_t bRing, uint8_t iReg) { if ( uSel > X86_SEL_RPL && !(uSel & X86_SEL_LDT) ) { if (uSel >= BS3_SEL_R0_FIRST && uSel < BS3_SEL_R0_FIRST + (5 << BS3_SEL_RING_SHIFT)) { /* Convert BS3_SEL_R*_XXX to the target ring. */ uSel &= BS3_SEL_RING_SUB_MASK; uSel |= bRing; uSel += BS3_SEL_R0_FIRST; uSel += (uint16_t)bRing << BS3_SEL_RING_SHIFT; } else { /* Convert TEXT16 and DATA16 to BS3_SEL_R*_XXX. */ uint16_t const uSelRaw = uSel & X86_SEL_MASK_OFF_RPL; if (uSelRaw == BS3_SEL_TEXT16) uSel = (BS3_SEL_R0_CS16 | bRing) + ((uint16_t)bRing << BS3_SEL_RING_SHIFT); else if (uSelRaw == BS3_SEL_DATA16) uSel = (BS3_SEL_R0_DS16 | bRing) + ((uint16_t)bRing << BS3_SEL_RING_SHIFT); /* CS and SS must have CPL == DPL. So, convert to standard selectors as we're usually here because Bs3SwitchToRing0 was called to get out of a test situation. */ else if (iReg == X86_SREG_CS || iReg == X86_SREG_SS) { if ( Bs3Gdt[uSel >> X86_SEL_SHIFT].Gen.u1Long && BS3_MODE_IS_64BIT_SYS(g_bBs3CurrentMode) ) uSel = iReg == X86_SREG_CS ? BS3_SEL_R0_CS64 : BS3_SEL_R0_DS64; else { uint32_t uFlat = Bs3SelFar32ToFlat32(0, uSel); bool fDefBig = Bs3Gdt[uSel >> X86_SEL_SHIFT].Gen.u1DefBig; if (!fDefBig && uFlat == BS3_ADDR_BS3TEXT16 && iReg == X86_SREG_CS) uSel = BS3_SEL_R0_CS16; else if (!fDefBig && uFlat == 0 && iReg == X86_SREG_SS) uSel = BS3_SEL_R0_SS16; else if (fDefBig && uFlat == 0) uSel = iReg == X86_SREG_CS ? BS3_SEL_R0_CS32 : BS3_SEL_R0_SS32; else { Bs3Printf("uSel=%#x iReg=%d\n", uSel, iReg); BS3_ASSERT(0); return uSel; } uSel |= bRing; uSel += (uint16_t)bRing << BS3_SEL_RING_SHIFT; } } /* Adjust the RPL on tiled and MMIO selectors. */ else if ( uSelRaw == BS3_SEL_VMMDEV_MMIO16 || uSelRaw >= BS3_SEL_TILED) uSel = uSelRaw | bRing; } } return uSel; } /** * Transforms a register context to a different ring. * * @param pRegCtx The register context. * @param bRing The target ring (0..3). * * @note Do _NOT_ call this for creating real mode or v8086 contexts, because * it will always output a protected mode context! */ #undef Bs3RegCtxConvertToRingX BS3_CMN_DEF(void, Bs3RegCtxConvertToRingX,(PBS3REGCTX pRegCtx, uint8_t bRing)) { if ( (pRegCtx->rflags.u32 & X86_EFL_VM) || pRegCtx->bMode == BS3_MODE_RM) { pRegCtx->rflags.u32 &= ~X86_EFL_VM; pRegCtx->bMode &= ~BS3_MODE_CODE_MASK; pRegCtx->bMode |= BS3_MODE_CODE_16; pRegCtx->cs = bs3RegCtxConvertRealSegToRingX(pRegCtx->cs, bRing); pRegCtx->ss = bs3RegCtxConvertRealSegToRingX(pRegCtx->ss, bRing); pRegCtx->ds = bs3RegCtxConvertRealSegToRingX(pRegCtx->ds, bRing); pRegCtx->es = bs3RegCtxConvertRealSegToRingX(pRegCtx->es, bRing); pRegCtx->fs = bs3RegCtxConvertRealSegToRingX(pRegCtx->fs, bRing); pRegCtx->gs = bs3RegCtxConvertRealSegToRingX(pRegCtx->gs, bRing); } else { pRegCtx->cs = bs3RegCtxConvertProtSelToRingX(pRegCtx->cs, bRing, X86_SREG_CS); pRegCtx->ss = bs3RegCtxConvertProtSelToRingX(pRegCtx->ss, bRing, X86_SREG_SS); pRegCtx->ds = bs3RegCtxConvertProtSelToRingX(pRegCtx->ds, bRing, X86_SREG_DS); pRegCtx->es = bs3RegCtxConvertProtSelToRingX(pRegCtx->es, bRing, X86_SREG_ES); pRegCtx->fs = bs3RegCtxConvertProtSelToRingX(pRegCtx->fs, bRing, X86_SREG_FS); pRegCtx->gs = bs3RegCtxConvertProtSelToRingX(pRegCtx->gs, bRing, X86_SREG_GS); } pRegCtx->bCpl = bRing; }